We gave up on the native iOS calendar app in favor of Fantastical months ago, but Tempo Smart Calendar is here to challenge for the throne. What makes Tempo so special? Well, it's made by SRI, the same group that invented Siri…yep, the same Siri that Apple later acquired. What Tempo does is pull in information from your calendar, contact list, email, and services like Facebook, Twitter, LinkedIn, and Foursquare. Using all of that data, it's able to pull in and give contextual data on all your calendar entries, including things like nearby parking, and the ability to send everyone else a message that you'll be late, right from within the app. Wanna wish your Facebook friends a "happy birthday" automatically? Tempo can handle that, too. Check the video out after the break, it does a great job of explaining it all.

You can download Tempo for free, right now, but you may have a challenge logging in once you have it. Tempo servers are being crushed under heavy load right now (a massive fail) and thousands are being left out in the cold currently.